The act of reposting a clever, interesting or funny comment from someone else's Facebook page and passing it off as your own.
This phenomenon is often observed after a widely commented on, important or tragic event occurs.
I will Rebook that post since it was such a great idea.
Person A: Man, I posted that joke about Bin Laden hours ago! Everyone is copying it!
Person B: Sorry dude, it's been Rebooked 100's of times now...
Person A: Fuck you mean?